Diesel low sulfur

In addition to greenhouse benefits, biodiesels offer environmental advantages over conventional diesel. Biodiesels produce similar NO, emissions to conventional diesel, fuel but less particulate matter. Biodiesel is more biodegradable that conventional diesel making any spills less damaging in sensitive areas. In general biodiesel provides more lubrication to the fuel system than low-sulfur diesel. 

Tippett, T. Knudsen, K. G., and Cooper, B., Ultra Low Sulfur Diesel Catalyst and Process Options, in NPRA Annual Meeting, 1999., Paper 99-06. 

Energy Information Agency. The Transition to Ultra-Low-Sulfur Diesel Fuel Effects on Prices and Supply. Special Report. 2001 May. Available from http //www.eia.doe.gov/oiaf/ servicerpt/ulsd/pdf/ulsd.pdf. 

Interim Reqnirements for Deposit Control Gasoline Additives Reid Vapor Pressnre Limitation Oxygenated Fnel Reqnirement Lead Phaseout Reformulated Gasoline Low-Sulfur Diesel Permits... 

Production of low-sulfur kerosene and low-sulfur diesel fuel. 

In the United States and other parts of the world, both low-sulfur diesel fuel and high-sulfur diesel fuel are being refined. Because fuel sulfur level has been identified as the primary component of fuel emission particulates and acid rain, sulfur reduction has been mandated and implemented. 

Hydroprocessing is utilized to reduce fuel sulfur concentrations. Fuels classed as high-sulfur diesel typically contain up to 5000 ppm of sulfur. Fuels classed as low-sulfur diesel typically contain up to 500 ppm of sulfur. Ultra-low sulfur or sulfur-free fuels typically have sulfur values of 15 ppm or less. 

Severely hydroprocessed ultra-low sulfur diesel fuel can differ in properties and performance from higher-sulfur-content diesel fuels. Some important differences are described here. 

Severely hydroprocessed ultra-low sulfur diesel fuel has poorer lubricity properties than higher-sulfur-content fuels. Many of the compounds that contribute to providing adequate lubricity have been removed. Metal wear and loss of fuel pump pressure can occur if fuel with poor lubricity is used. 

Conversion of heterocyclic aromatic compounds or other aromatic fuel components to paraffins by hydroprocessing can help increase the cetane number of diesel fuel. Fuel paraffins have significantly higher cetane number values than fuel aromatics. For this reason, the cetane number of ultra-low sulfur diesel fuel will typically be one to five numbers greater than higher-sulfur grade fuels. 

Although hydroprocessing will remove most of the naturally occurring antioxidants contained in fuel, other less stable, more reactive components will also be reduced. As a whole, ultra-low sulfur diesel fuel will be much less prone to color degradation and deposit formation than earlier-era diesel fuels. 

FIGURE 4-3. Water Solubility in a Typical Low-Sulfur Diesel Fuel... 

FIGURE 4-7. Effect of Kerosene Blending on the CFPP of Low-Sulfur Diesel... 

If a diesel fuel is low in viscosity due to kerosene dilution or solvent dilution, its lubricity is probably poor. The possibility of wear of the high-pressure fuel injection pump parts will increase. The effect of kerosene dilution on the lubricity of a typical low sulfur diesel fuel is shown in FIGURE 5-2. 

FIGURE 5-2. Effect of Kerosene Dilution on Low-Sulfur Diesel Fuel Lubricity... 

Since the introduction of low-sulfur diesel fuel, much study has been completed to determine the lubricity properties of this fuel. Comparison of low-sulfur diesel with high-sulfur diesel has clearly revealed that fuel sulfur has a dramatic impact on the ability of fuel to provide a higher level of lubricity performance. A comparison of the lubricity performance of a typical high-sulfur diesel low-sulfur diesel and low-aromatic, low-sulfur diesel is shown in FIGURE 5-3. 

The effect of increased levels of cetane improver on the Conradson Carbon value of a typical low-sulfur diesel fuel is illustrated in FIGURE 5-6. 

Because of the low-sulfur, -nitrogen, and -aromatic content of Fischer-Tropsch fuels, there is renewed interest in these products. In two recent studies, Fischer-Tropsch diesel was evaluated and compared to an ultra-low sulfur California diesel and to a 49 cetane number, low-sulfur diesel. In the two studies, carbon monoxide, nitrogen oxide, hydrocarbon, particulate, and carbon dioxide emissions were reduced in vehicles fuels by Fischer-Tropsch diesel. The fuel economy, however, was also reduced. The low aromatic content and high concentration of waxlike hydrocarbons in Fischer-Tropsch diesel can lead to the need for special handling and treatment of the fuel to prevent gelling when used in cold-temperature conditions. 

Bluth, Matt J. 1997. (Internal report) Low sulfur diesel CFPP reduction. 97/423. Sugar Land, Tex. Nalco/Exxon Energy Chemicals, L.P. 

The ANL catalyst (not identified, but presumably a Pt supported on Gd-doped ceria) was also successfully used for ATR of diesel fuel. Tests of three different types of diesel fuels (n-Cie, low-sulfur diesel, and regular diesel) showed complete conversion of hydrocarbons at 800°C. The diesel surrogate n-Ci6 yielded 60% H2 on a dry, N2-free basis at 800°C, whereas the other two diesel fuels required higher temperatures (>850°C) to yield similar levels of H2 in the product gases. Similar or improved H2 yields from diesel ATR were observed with a microchannel monolith catalyst, compared with extruded pellets in a fixed-bed reactor. ... 

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